api/simple-mat: move euler stuff to dedicated namespace

1 files changed, 98 insertions, 0 deletions

diff --git a/opentrack/simple-mat.cpp b/opentrack/simple-mat.cpp
new file mode 100644
index 00000000..45a6ef5b
--- /dev/null
+++ b/opentrack/simple-mat.cpp
@@ -0,0 +1,98 @@
+#include "simple-mat.hpp"
+
+namespace euler {
+
+static constexpr double pi = 3.141592653;
+
+enum Axis
+{
+    TX, TY, TZ, Yaw, Pitch, Roll
+};
+
+static constexpr double eps_ = 1e-1;
+static constexpr double d2r = pi / 180;
+static constexpr double eps = eps_ * d2r;
+
+euler_t euler_filter(const euler_t& rot_)
+{
+    using std::fabs;
+    using std::copysign;
+
+    euler_t rot(rot_);
+
+    static constexpr double thres[] =
+    {
+        pi, pi/2, pi
+    };
+
+    for (int i = 0; i < 3; i++)
+        if (fabs(rot(i)) > thres[i] - eps && fabs(rot(i)) < thres[i] + eps)
+        {
+            const double eps__ = copysign(eps, rot(i));
+            rot(i) -= eps__;
+            rmat tmp = euler_to_rmat(rot);
+            rot = rmat_to_euler(tmp);
+            rot(i) += eps__;
+        }
+    return rot;
+}
+
+euler_t rmat_to_euler(const dmat<3, 3>& R)
+{
+    static constexpr double pi = 3.141592653;
+    const double pitch_1 = asin(-R(0, 2));
+    const double pitch_2 = pi - pitch_1;
+    const double cos_p1 = cos(pitch_1), cos_p2 = cos(pitch_2);
+    const double roll_1 = atan2(R(1, 2) / cos_p1, R(2, 2) / cos_p1);
+    const double roll_2 = atan2(R(1, 2) / cos_p2, R(2, 2) / cos_p2);
+    const double yaw_1 = atan2(R(0, 1) / cos_p1, R(0, 0) / cos_p1);
+    const double yaw_2 = atan2(R(0, 1) / cos_p2, R(0, 0) / cos_p2);
+
+    using std::fabs;
+
+    const double err1 = fabs(pitch_1) + fabs(roll_1) + fabs(yaw_1);
+    const double err2 = fabs(pitch_2) + fabs(roll_2) + fabs(yaw_2);
+
+    if (err1 > err2)
+    {
+        bool fix_neg_pitch = pitch_1 < 0;
+        return euler_t(yaw_2, fix_neg_pitch ? -pi - pitch_1 : pitch_2, roll_2);
+    }
+    else
+        return euler_t(yaw_1, pitch_1, roll_1);
+}
+
+// tait-bryan angles, not euler
+rmat euler_to_rmat(const double* input)
+{
+    static constexpr double pi = 3.141592653;
+    auto H = input[0] * pi / 180;
+    auto P = input[1] * pi / 180;
+    auto B = input[2] * pi / 180;
+
+    const auto c1 = cos(H);
+    const auto s1 = sin(H);
+    const auto c2 = cos(P);
+    const auto s2 = sin(P);
+    const auto c3 = cos(B);
+    const auto s3 = sin(B);
+
+    double foo[] = {
+        // z
+        c1 * c2,
+        c1 * s2 * s3 - c3 * s1,
+        s1 * s3 + c1 * c3 * s2,
+        // y
+        c2 * s1,
+        c1 * c3 + s1 * s2 * s3,
+        c3 * s1 * s2 - c1 * s3,
+        // x
+        -s2,
+        c2 * s3,
+        c2 * c3
+    };
+
+    return dmat<3, 3>(foo);
+}
+
+} // end ns euler